Microwave ovens have become a permanent fixture in many home kitchens and high volume industrial applications. For example, the tempering of large quantities of frozen meat, fish, poultry and fruit is greatly enhanced with the use of microwave ovens. Not only do microwave ovens provide for greater uniformity in processing, they also eliminate an otherwise several hour wait time to thaw a frozen product prior to its availability for use, while minimizing drip loss and improving sanitation.
One example of the uses of microwave technology is taught by in U.S. Pat. No. 6,274,858, issued to Alton, et al., is directed to a feed that provides circularly polarized microwave energy for energizing a microwave oven. The feed includes a transformer to match a linearly polarized rectangular waveguide to a polarization waveguide section that may be circular or square in cross section. In one embodiment, the asymmetrical element provides symmetry about a plane only. The asymmetrical element introduces a difference in microwave electrical phase for polarizations which are respectively parallel to and perpendicular to the symmetry plane. A second waveguide section having a bend is also used in the feed assembly, which may be a bent section of circular waveguide and presents an electromagnetic symmetry about a plane only. As a result, the two waveguide sections operating together provide circularly polarized energy at constant magnitude but continually rotating phase.
U.S. Pat. No. 7,154,103 issued to Koenck, et al., is directed to a method that includes irradiating the meat products in a first controlled atmosphere that excludes oxygen and packaging the irradiated meat products in a second controlled atmosphere that is high in oxygen. The packaged irradiated meat products are then distributed to a retail store. An antioxidant may be added to the meat products either prior to or following the step of irradiating the meat products in the first controlled atmosphere, to extend the color-life of the meat products.
U.S. Pat. No. 6,546,646 issued to Thomas is directed to a process and apparatus for removing moisture from a material, without spoiling the processed product, through the implementation of microwave irradiation heating, drying, dehydration, curing, disinfection, pasteurization, sterilization or vaporization or any combination thereof.
U.S. Pat. No. 6,496,736 issued to Carl, et al., is directed to a Method and apparatus are provided to treat atherosclerosis wherein the artery is partially closed by dilating the artery while preserving the vital and sensitive endothelial layer thereof. Microwave energy having a frequency from 3 GHz to 300 GHz is propagated into the arterial wall to produce a desired temperature profile therein at tissue depths sufficient for thermally necrosing connective tissue and softening fatty and waxy plaque while limiting heating of surrounding tissues including the endothelial layer and/or other healthy tissue, organs, and blood.
U.S. Pat. No. 5,440,104 issued to Koch, et al., is directed to a process for a uniform and fast heating of products by microwaves that are pulsed and introduced intermittently into the products, with the products to be treated, such as chemical or pharmaceutical products or foodstuffs, particularly ready-cooked meals, being conveyed by a continuously working endless conveyor belt through a treatment chamber in open or closed microwave-permeable trays and with the treatment chamber being equipped with microwave generator supply channels that are arranged in a vertical or inclined position relative to the conveyor belt.
U.S. Pat. No. 4,808,783 issued to Stenstrom, is directed to a continuous method for heating a product having at least one faster microwave heating portion and at least one slower microwave heating portion to a uniform predetermined temperature sufficient to sterilize the product without loss of odor, taste, texture, color or vitamin content quality by transporting the product through a plurality of microwave fields including a first higher energy field and one or more successively lower energy fields, in which the first microwave field is attenuated to an energy level sufficient to heat the fast microwave heating portions of the product to the predetermined temperature, the successively lower energy microwave fields are attenuated to an energy level sufficient to maintain the temperature of the faster heating portions and heat the slower heating portions to the predetermined temperature, and the transport of the product through the successively lower energy microwave fields is continued until the slower microwave heating portions of the product reach the predetermined temperature.
U.S. Pat. No. 4,524,079 issued to Hofmann is directed to an invention where Material having relatively high electrical resistivity, such as food products and containers, is disposed within a magnetic coil and subjected to one or more pulses of an oscillating magnetic field having an intensity of between about 2 and about 100 Tesla and a frequency of between about 5 and about 500 kHz. A single pulse of the magnetic field generally decreases the microorganism population by at least about two orders of magnitude, and substantially complete sterility is more closely approached by subjecting the material to additional pulses.
U.S. Pat. No. 5,962,054 issued to Kozempel, et al., is directed to a process that has been developed for the non-thermal treatment of liquid food products which results in a significant reduction in the microbial population, thus reducing spoilage and extending shelf life. The novel process involves the rapid application of electromagnetic energy (EME), such as microwave or radio frequency energy, and the simultaneous removal of any thermal energy which may be generated by the process through the use of circulating cooling medium and an efficient heat exchanger.
U.S. Pat. No. 5,667,828 issued to Nikdel, et al., is directed to a system and method for pasteurizing citrus juice with the use of microwave energy provide a plurality of microwave chambers through which juice is continuously flowed, the sequential flowing permitting a gradual increase in juice temperature that is sufficient to pasteurize the juice but insufficient to cause a detectable loss of flavor.
U.S. Pat. No. 5,389,335 issued to Charm, et al., is directed to a high temperature, short time microwave heating system 10 for heat-sensitive liquid material to inactivate or reduce pathogenic agents or organisms, such as viral contaminants.
U.S. Pat. No. 4,624,854 issued to Naumann, et al. is directed to a method of continuously sterilizing foodstuff and an apparatus suitable for carrying out the method are disclosed. The invention, which permits a considerable saving in the amount of microwave energy to be achieved, is attained by providing a plurality of sequential stages in each of which the foodstuff is subjected to microwave radiation, the temperature of the article being sterilized being monitored in each stage and the amount of microwave energy being reduced from stage to stage in a stepwise manner in dependence upon the temperatures monitored.
United States Patent Application No. 20040156958 filed by Nissim, et al., is directed to the manufacture and assembly of food packages that possess all of the advantages of packages, and keep product in good condition or remain product safe quality during transport process, keep this product in good condition at keeping process as well, and also keep this product in good condition during sale and in non-bacteria atmosphere always. The method uses decreased vacuum while the safest time is increased for all food products drastically. The characteristic feature of filter package is that filter can consist of microchip for increasing filter efficiency and filter capability, and substance treating of small and big particles removing of contamination and poisoning of substance. The package of manufactured food product can be folded most time when package is not used and is made mostly from hard plastic material or another nonmetal.
Preventing the growth of mold spores has been a challenging task since the beginning of time. While mold and bacterial growth are constantly present and virtually impossible to eliminate due to rapid growth, inhibiting expansion has proven to be an especially the daunting task. Such challenges are especially prevalent with consumable goods.
While entire colonies of mold growth can be eliminated using conductive, convective, and radioactive procedures, the original foodstuff qualities of the consumable good are often destroyed in the process. For example, using a toaster oven to cook a piece of bread will most certainly reduce if not eliminate the amount of microbial growth, yet the original firmness and palatability have changed during the heat input into the bread. Using prolonged microwave radiation also has a similar effect and perhaps eliminates more mold than standardized heating techniques, yet uncontrolled amounts of radiation destroys the original product's identity.
Presently, conduction and convection are most commonly used to destroy mold colonies. Most commonly perceived among the general public is a thought similar to the functionality of boiling water; if enough heat is applied to the matter, both bacteria growth and its physical presence will be destroyed. Perhaps this thought is so prevalent because the application of heat often materially alters the physical characteristics of a food-stuff in question. For example, when moldy bread is toasted, the whitish color with green of bleu speckles often changes to brown or black. Yet when moldy bread is placed into a microwave a similar discoloration does not occur. Thus the original mold spores although exterminated, appear present, as a lack of discoloration often results in this common deception.
Using heat and radioactive energy to destroy mold, bacteria, and other microbial organism is relatively simple and widely known, yet exact quantities of minimal energy are not known. The input of enough heat or radioactive energy into a living organism will ultimately prevent its further existence. While thermodynamic science has revealed the precise calculations for necessary heat input to provide for the destruction of microbial growth, an equivalent function provided by radiation remains a mystery. While science may reveal that subjecting a food-stuff to microwave radiation for over five minutes should do the trick, the prior art is yet to teach a less invasive method that radioactively expels bacterial growth while maintaining a food stuff's original identity performed over a minimal time duration.